org.kiwiproject.dropwizard.util.lifecycle.StandardLifecycles Maven / Gradle / Ivy

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Set of utilities to aid in setting up Dropwizard services
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package org.kiwiproject.dropwizard.util.lifecycle;

import static org.kiwiproject.base.KiwiPreconditions.checkArgumentNotBlank;
import static org.kiwiproject.base.KiwiPreconditions.checkArgumentNotNull;
import static org.kiwiproject.base.KiwiStrings.f;

import io.dropwizard.core.setup.Environment;
import lombok.experimental.UtilityClass;
import lombok.extern.slf4j.Slf4j;
import org.kiwiproject.registry.config.ServiceInfo;
import org.kiwiproject.registry.management.RegistrationManager;
import org.kiwiproject.registry.management.dropwizard.RegistrationLifecycleListener;
import org.kiwiproject.registry.server.RegistryService;

import java.time.Instant;
import java.util.OptionalLong;
import java.util.concurrent.ScheduledExecutorService;
import java.util.regex.Pattern;

/**
 * Contains some "standard" static utilities related to Dropwizard and Jetty lifecycles.
 */
@UtilityClass
@Slf4j
public class StandardLifecycles {

    private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\s");
    private static final String EMPTY_STRING = "";

    /**
     * Logs the given server status. For example, you can use this to log the successful startup of a service in
     * a consistent manner.
     *
     * @param status the status of the server
     * @implNote This is logging at WARN level so that even in a production-like environment where logging levels
     * may be set to WARN, the server startup will always be logged.
     */
    public static void logServiceStatusWarningWithStatus(String status) {
        LOG.warn("==========================================================================");
        LOG.warn("SERVICE IS {}: {}", status, Instant.now());
        LOG.warn("==========================================================================");
    }

    /**
     * Adds lifecycle listeners to the Dropwizard environment that will register and unregister the service at
     * startup and shutdown, respectively.
     *
     * @param registryService a pre-built {@link RegistryService} that will connect to a service discovery for
     *                        registration/un-registration
     * @param serviceInfo     the metadata about the service (i.e. name, version, etc.)
     * @param environment     the Dropwizard environment
     */
    public static void addRegistryLifecycleListeners(RegistryService registryService,
                                                     ServiceInfo serviceInfo,
                                                     Environment environment) {

        var registrationManager = new RegistrationManager(serviceInfo, registryService);

        var listener = new RegistrationLifecycleListener(registrationManager);

        // Handles registering at startup
        environment.lifecycle().addServerLifecycleListener(listener);

        // Handles unregistering at shutdown
        environment.lifecycle().addEventListener(listener);
    }

    /**
     * Adds a server lifecycle listener that logs the server connector information on startup.
     *
     * @param environment the Dropwizard environment
     */
    public static void addServerConnectorLoggingLifecycleListener(Environment environment) {
        environment.lifecycle().addServerLifecycleListener(new ConnectorLoggingServerLifecycleListener());
    }

    /**
     * Adds a lifecycle listener that logs the current process id on startup.
     *
     * @param processId   the process id or an empty optional if unable to find it
     * @param environment the Dropwizard environment
     * @implNote Yes, the generally accepted wisdom is that Optional arguments are "bad". However, in this
     * situation we make an exception to that "rule" to support the case when a {@link Process#pid()} does not
     * support getting the pid. Our kiwi library has a {@link org.kiwiproject.base.KiwiEnvironment#tryGetCurrentPid()}
     * which returns {@link OptionalLong}, and this method makes it convenient to take the result of that method
     * and supply it directly to this method without converting it.
     */
    public static void addProcessIdLoggingLifecycleListener(OptionalLong processId, Environment environment) {
        if (processId.isPresent()) {
            addProcessIdLoggingLifecycleListener(processId.getAsLong(), environment);
        } else {
            addProcessIdLoggingLifecycleListener((Long) null, environment);
        }
    }

    /**
     * Adds a lifecycle listener that logs the current process id on startup.
     *
     * @param processId   the process id
     * @param environment the Dropwizard environment
     */
    public static void addProcessIdLoggingLifecycleListener(long processId, Environment environment) {
        environment.lifecycle().addServerLifecycleListener(new ProcessIdLoggingServerLifecycleListener(processId));
    }

    /**
     * Adds a lifecycle listener that logs the current process id on startup.
     *
     * @param processId   the process id or null if unable to find it
     * @param environment the Dropwizard environment
     */
    public static void addProcessIdLoggingLifecycleListener(Long processId, Environment environment) {
        environment.lifecycle().addServerLifecycleListener(new ProcessIdLoggingServerLifecycleListener(processId));
    }

    /**
     * Adds a lifecycle listener to print out the status of the server with configured ports at startup.
     *
     * @param serviceInfo the metadata about the service (i.e. name, version, etc.)
     * @param environment the Dropwizard environment
     */
    public static void addServiceRunningLifecycleListener(ServiceInfo serviceInfo, Environment environment) {
        environment.lifecycle().addServerLifecycleListener(new ServerStatusServerLifecycleListener(serviceInfo));
    }

    /**
     * Create a new {@link ScheduledExecutorService} whose lifecycle is managed by Dropwizard.
     *
     * @param env  the Dropwizard environment
     * @param name the name of the executor (whitespace will be removed e.g. "My Executor" will become "MyExecutor")
     * @return a new ScheduledExecutorService instance attached to the lifecycle of the given Dropwizard environment
     * @see Environment#lifecycle()
     * @see io.dropwizard.lifecycle.setup.LifecycleEnvironment#scheduledExecutorService(String)
     */
    public static ScheduledExecutorService newScheduledExecutor(Environment env, String name) {
        checkArgumentNotNull(env, "Dropwizard Environment must not be null");
        checkArgumentNotBlank(name, "name must not be blank");

        var safeName = f("Scheduled-{}-%d", WHITESPACE_PATTERN.matcher(name).replaceAll(EMPTY_STRING));
        return env.lifecycle()
                .scheduledExecutorService(safeName, true)
                .build();
    }
}